Solution equilibrium and redox properties of metal complexes with 2-formylpyridine guanylhydrazone derivatives: Effect of morpholine and piperazine substitutions.

Schiff bases derived from aminoguanidine are extensively investigated for their structural versatility. The tridentate 2-formylpyridine guanylhydrazones act as analogues of 2-formyl or 2-acetylpyridine thiosemicarbazones, where the thioamide unit is replaced by the guanidyl group. Six derivatives of 2-formylpyridine guanylhydrazone were synthesized and their proton dissociation and complex formation processes with Cu(II), Fe(II) and Fe(III) ions were studied using pH-potentiometry, UV-visible, NMR and electron paramagnetic resonance spectroscopic methods.

Organometallic Half-Sandwich Complexes of 8-Hydroxyquinoline-Derived Mannich Bases with Enhanced Solubility: Targeting Multidrug Resistant Cancer.

Drug resistance is a major obstacle in cancer treatment. Herein, four novel organometallic complexes, with the general formula [Ru(η--cymene)(HL)Cl]Cl and [Rh(η-CMe)(HL)Cl]Cl, were developed to target multidrug-resistant (MDR) cancer cells, where HL denotes 8-hydroxyquinoline-derived Mannich bases (HQCl-pyr and HQCl-pip). The aim of the complexation was to obtain compounds with improved drug-like properties.

How reliable is the evaluation of DNA binding constants? Insights and best practices based on an inter-laboratory fluorescence titration study.

In all experimental sciences, the precision and reliability of quantitative measurements are paramount. This is particularly true when examining the interactions between small molecules and biomolecules/polyelectrolytes, such as DNAs/RNAs, and yet it is overlooked in most publications of thermodynamic binding parameters. This paper presents findings from COST Action 18202 "Network for Equilibria and Chemical Thermodynamics Advanced Research," which assessed the consistency of data derived from the interactions of calf-thymus DNA (CT-DNA) with the fluorescent intercalator ethidium bromide (EB) through spectrofluorimetric titrations.

Are the metal identity and stoichiometry of metal complexes important for colchicine site binding and inhibition of tubulin polymerization?

Quite recently we discovered that copper(II) complexes with isomeric morpholine-thiosemicarbazone hybrid ligands show good cytotoxicity in cancer cells and that the molecular target responsible for this activity might be tubulin. In order to obtain better lead drug candidates, we opted to exploit the power of coordination chemistry to (i) assemble structures with globular shape to better fit the colchicine pocket and (ii) vary the metal ion. We report the synthesis and full characterization of bis-ligand cobalt(III) and iron(III) complexes with 6-morpholinomethyl-2-formylpyridine 4-(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL1), 6-morpholinomethyl-2-acetylpyridine 4-(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL2), and 6-morpholinomethyl-2-formylpyridine 4-phenyl-3-thiosemicarbazone (HL3), and -ligand nickel(II), zinc(II) and palladium(II) complexes with HL1, namely [Co(HL)(L)](NO) (1), [Co(HL)(L)](NO) (2), [Co(HL)(L)](NO) (3), [Fe(L)]NO (4), [Fe(HL)(L)](NO) (5), [Ni(L)]Cl (6), [Zn(L)Cl] (7) and [Pd(HL)Cl]Cl (8).